Which tool to choose
They're not all the same: the choice depends on what you really need.
You want a written plan, free and editable with words → a conversational AI. ChatGPT on the free plan is more than enough: free users can search the web, analyze data, upload images or files and generate images. The limit is the message cap, but to build a plan you need few of them. As an alternative, Claude (claude.ai), equally good at long, orderly text. This is the profile for those who want total control: you change an exercise, ask for a variant for the knee, move a day, all by writing.
You want to be guided by video during execution → a dedicated app with integrated AI. Freeletics builds and adapts the plan on its own: after an initial test it generates a personalized bodyweight program that changes over time based on your feedback. It costs: to expand the set of programs you need the Training subscription, starting from about 37.50 euros a year.
You want a human coach and live classes → Buddyfit. The strong point is the flesh-and-blood professional trainers, whose classes you follow recorded or live; the videos are in Italian and designed for working out at home, with or without equipment. Note: it doesn't offer a free trial and the cost is about €17.99 a month or €59.99 a year.
The rest of this guide follows the first path (the conversational AI), because it's free, immediate and leaves you in full control.
How to do it
From a browser or from the app, the path doesn't change:
- Go to chatgpt.com (or open the ChatGPT app) and log in with a free account.
- Open a new chat.
- Paste the prompt below, modifying only the data in quotes.
- Read the plan and, if something doesn't add up, reply in the same chat to have it corrected.
The operational syntax:
You are a personal trainer. Create me a weekly bodyweight workout
plan, to do at home without any equipment.
Data about me:
- Age: 38 years old
- Sex: man
- Weight and height: 82 kg, 178 cm
- Level: beginner, off for 2 years
- Available days: 3 a week, about 30 minutes per session
- Goal: get back in shape and lose a bit of belly
- Physical limits: discomfort in the right knee, avoid jumps
I want for each day:
- warm-up (3-4 minutes)
- the exercises with number of sets, reps and seconds of recovery
- cool-down and final stretching
- a progression: what to change every 2 weeks so I don't stall
Explain each exercise in one line, so I understand how to perform it.
Don't include exercises that require equipment or weights.
Feedback: a valid plan must specify sets, reps and recovery for each exercise, include warm-up and stretching, and respect your limits (in the example, zero jumps). If one of these elements is missing, it's not ready: reply "the recovery times are missing, add them" and the AI regenerates only that piece.
For those who train reading from their phone while performing, add at the end of the prompt:
Rewrite the plan in a compact list format, without explanations,
so I can read it during the workout.
Concrete example
Marco, 38 years old, sedentary for two years, three free evenings a week. He pastes the prompt above. ChatGPT gives him back three 30-minute total-body sessions: Monday legs and core, Wednesday push (push-ups on knees, chair dips), Friday mixed circuit. For the knee it replaces lunges with the glute bridge and wall sits, no jumps.
Marco notices that the full push-ups are too much and writes: "I can't do floor push-ups, give me an easier version". The AI replaces them with wall push-ups and then on a raised surface, indicating when to move to the next version. Marco copies the plan into his phone's notes and starts. After two weeks he asks: "I finished the first two weeks without problems, raise the difficulty". He receives the progression: +2 reps per set and an optional fourth day. All of this is iterative personalization: the real difference between AI and a static plan found online.
This total-body approach is the one recommended by professionals: home workouts without equipment focus on exercises that train several muscle groups together, alternating intense work and recovery.
When it does NOT work (and how to fix it)
If the AI invents strange or dangerous exercises
Sometimes the AI proposes movements with made-up names or technically questionable ones. Fix: ask "For each exercise, tell me the common name in Italian and in English, so I can look it up on YouTube". Seeing the movement performed by a professional protects you. Always do a good warm-up before starting and finish with some stretching: insist on these two blocks in the plan.
If you run out of free messages halfway
On the free plan the cap is low: Free accounts have a limited number of messages within a window of a few hours. Fix: build the plan in a single well-made message (like the prompt above) instead of many little questions. If you get blocked, waiting a few hours resets the counter without paying anything.
If the plan is too generic
It happens when the prompt is poor. Fix: the more data you give, the more the plan is tailored to you. Add how many times a week you train, how many real minutes you have, and above all your physical limits. A home-made plan has a precise advantage: it costs little and lets you modulate the type and intensity of the exercises to your level. Exploit it by telling the AI exactly your starting point.
If you have pain or conditions
The AI doesn't replace a doctor. If you have heart problems, serious joint issues, are pregnant or recovering from an injury, have the plan validated by a physiotherapist or doctor before starting. It's a check of a few minutes that saves you weeks of being stopped.
A tip from someone who actually uses it
Don't close the chat after getting the plan: keep it open and use it as a diary. Every weekend write to the AI what went well and what didn't ("day 2 was too easy, the glute bridge pulled my back") and have the plan updated. That's how the workout stops being a dead sheet and becomes a path that grows with you. Save the chat link in your bookmarks: it's your complete log, always within reach.
Frequently asked questions
Can I use AI for the plan for free without paying anything?
Yes. ChatGPT on the free plan creates a complete plan at no cost. It's a solid feature set for personal use. The only constraint is the number of messages within a window of a few hours, irrelevant for building a plan.
Better ChatGPT or a dedicated fitness app?
It depends on how you train. If you want a plan to modify with words and read while performing, ChatGPT wins for flexibility and cost. If you need a video that shows the movement and paces the timing, a dedicated app is more suitable: apps like Freeletics or Garmin Connect offer ready-made workouts with animated clips on correct execution and work and rest timers. Many combine them: plan with the AI, video of the single exercise on YouTube.
Do I have to give my personal data to the AI for the plan?
You only need data useful for the workout: age, weight, level, goals, physical limits. There's no need for your real name, address or documents. If privacy worries you, use a nickname and give only the numbers needed to calibrate the exercises.
Can AI really replace a personal trainer?
No, and anyone promising it is selling you something. The AI is excellent for designing and adapting a basic bodyweight plan, and for most people this is more than enough to get moving again. But it doesn't see your posture, it doesn't correct an execution error in real time and it doesn't notice if you're compensating with your back. For advanced goals, rehabilitation or fine technique, a human eye remains irreplaceable: the AI takes you from the start to the first milestone, not beyond.